Abstract: Exposure to volatile organic compounds (VOCs) occurs commonly in everyday life. Accurate assessment of the risk to public health posed by VOCs requires both the quantification of these exposures on a population-wide basis and the evaluation of potential health effects associated with varying exposure levels. Preliminary analyses that we have done show that in the NHANES III data an association exists between blood levels of selected VOCs and abnormal liver function tests. We propose to conduct a thorough examination of the potential effects of personal exposure to VOCs on liver function, using the data from NHANES 1999-2000. We will investigate whether there are independent effects or if the effects are modified by alcohol consumption and use of pain medications. In addition, we will examine the associations between exposure to a cluster of VOCs and biochemical markers of liver function after grouping toxicologically similar VOCs. VOC exposure status will be described according to the personal monitoring data for ten VOCs. Biochemical markers of liver function included serum concentrations of albumin, bilirubin, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, and 3-glutamyl transferase. Levels of these biomarkers will be compared by different exposure levels. Multiple linear regression and logistic models will be used to examine whether there is a linear association or a threshold effect which occurs only at relatively high levels of exposure. The analyses will also be performed for subgroups. By examining the relationship of sensitive markers of liver function and individual exposure monitoring data in a large national sample, this proposed study is able to detect a subtle/subclinical effect of VOCs at relatively low exposure levels. The assessment of possible interactions of VOC exposure with alcohol consumption and medication use may help to identify susceptible subgroups. If the effect of background VOC exposure on liver function is identified, then regulation can be used to reduce the exposures implicated. If it is confirmed that liver-enzyme elevations in asymptomatic people are linked with environmental exposure to volatile organic compounds, the finding will be very useful to both individual and public health. Narrative We propose to conduct a thorough examination of the potential effects of personal exposure to VOCs on liver function, using the data from NHANES 1999-2000. By examining the relationship of sensitive markers of liver function and individual exposure monitoring data, this proposed study may be able to detect a subtle effect of VOCs at relatively low exposure levels. If the effect of background exposure on liver function is identified, then regulation can be used to reduce the exposures implicated. [unreadable] [unreadable] [unreadable]